Improved melting-furnaces foe the manufacture of steel



W; SWIN'DELL. Furnace for Making. Steel.

NO. 70.042- Patented Oct. 22, 1867;

ILPETERS, PHOTO'UTHOGRKPVKER, WASHINGTON. EC.

witch WILLIAM SWINDELL, OF ALLEGHENY CITY, PENNSYLVANIA.

' Letters Patent No. 70,042, dated October 22, 1867.

IMPROVED MEETING-FURNACES FOR THE MANUFACTURE UP STEEL.

tilts firlphule match to ill tlgese anon brunt amt mating gut Hi the same.

TO ALL WHOM IT MAY CONCERN;

Be it known that I, WILLIAM SWINDELL, of Alle heny City, in the county of Allegheny, and State of Penn sylvania, have invented a new and usefulImprovernent in Melting-Furnaces for the Manufacture of Steel; and

I do hereby declare the following to be a full, clear, and exact description thereof.

My improvement relates to the construction of furnaces for the manufacture of steel. The furnaces ordinari'ly used, in which are placed the cruciblcscpntaining the steel, are built of fire-brick, below the surface of the ground, and consist of cavities or chambers of rectangular shape, in horizontal section, with arched top, having a flue-hole near the top on one side, and an opening at top for the insertion of the crucibles and the fuel. The bottom of these chambers consists of grate-bars, and the space below the grate-bars connects with a passage to supply the necessary air to support combustion. A number of these furnaces or chambers are built together, in one mass of brick-work, each chamber being large enough to hold two crucibles and the fuel with which it is necessary to surround them. The fuel in these chambers does not reach to the top of the cavity or chamber, the flue being left uncovered, and as the heat is much greater in the lower than in the upper portionof the furnace the bricks near the bottom burn out much more rapidly than those at and near the top. With constant use one of these steel-furnaces burns out at the lower part, so as to require rebuilding, in six weeks, while the upper portion is still in good condition, The tearing down and rebuilding these furnaces so frequently is a great source of expense, and the chief object of my improvement is to construct these furnaces in such a manner as that the lower portion may be rebuilt without disturbing the upper part, and at a comparatively trifling cost. By my improved construction of these furnaces I also effect a great-saving in the number of bricks required to build each furnace. My furnaces will also last longer and heat more uniformly.

.To enable others skilled in the art to make use of my invention I will proceed to describe the peculiar construction of my steel-furnace. In the accompanying drawings- Figure I is an exterior vertical elevation of one of my improved furnaces.

Figure 2 is a vertical section through one of the furnaces,

Figure 3 is a horizontalsection through a: a: of fig. 2, and

Figure 4; is a top view of the furnace.

In the several figures like letters denote similar parts. v v

Instead of building several furnaces together, as a solid mass of brick-work, with the necessary cavities for receiving the crucibles, I build each furnace separate, leaving an open space between and all around them, which has the'double advantage of enabling the to rebuild or repair one without disturbing the others, and of allowing a-frce circulation of air around them, which prevents their burning out so rapidly.

On a foundation of brick-work, consisting of piers a a, I place an iron bottom plate, 0, supported by legs 6 b, by which each furnace is raised slightly above the foundation, the legs 6 b of the frame c resting on opposite piers, between which is the ash-pit d connecting with the airfiue. In the frame 0 is an opening, corresponding 'in size and shape with the cross-section of the cavity-or chamber 6 of the furnace, which may be rectangular,

but'I prefer to make it oblong, with parallel sides and semicircular ends, as in the drawing. To the bottom plate 0 I attach the bearing-bars jj, on which are placed the grate-bars ff, which support the crucibles g and the fuel, the grate-bars being placed across the opening in the bottom plate before referred to. In the bottom plate 0, around the opening-just mentioned, I make a nuniberof small apertures, it, which allow the air to pass in between the grate-bars on all sides, thus securing a better supply of air and a more uniform combustion of the fuel. To the bottom plate 0 I fasten, by means of bolts 2: :v, an upright frame or casing, consisting of castiron plates .5 h, which are bolted together at the sides by the bolts it :t, passing through lugs y 3/ at the edges of the casing-plates h it. These plates h It are soshaped that when put up and fastened together they form a shell of the shape of the furnace, which, as before stated, I prefer to make oblong, with two parallel sides and semicircular ends. This shape, which is also the shape of the cavity or chamber of the furnace, is adecidcd advantage over the rectangular chamber heretofore used, because it requires less brick where the furnaces are built separate from each other, and because it requires less fuel to be used. The iron easing or shell formed by the union of the plates it it has a. bottom pli'te, k, which rests on the bottom-plate c, and is covered when the furnace is built by the top plates Z Z, which are also of iron, and which extend beyond the edge of the casing,

so as to connect with the top plates of the eldjoining furnace, as seen in figs. 1 and 2, thus forming an iron floor on the level of the surface of the ground.

Figs. 1 and 2 in the drawing are connected together, to show the manner in which the separate furnaces are built, and the space m which is left between them, which-connects with the air-flue through the ash-pits (Z d, and thus allows the air to circulate freely around each separate furnace. The space m between the furnaces is covered on top by the plates ll. The casing or shell formed by the plates 7t h is lined internally with fire-brick n, the bricks resting on the plate It and being built up within the iron easing or shell so as to form a chamber, a, of the required shape and size, and leaving a flue, p, for the escape of the gaseous products of combustion of the fuel. The upper part of the chamber is contracted, leaving an opening, 9, at the top for the'inscrtion of the crucibles and of the fuel. The brick-work of the chamber does not need'to be so thick when thus supported by the casing as would otherwise be necessary, so that by' my construction of these furnaces I use but little more than one-half as many bricks as are now ordinarily required. In the iron plates h h are slits or, openings 7' 1, designed to allow air to pass in to the brick, and thus aid in keeping them cool.

These furnaces, likethose of ordinary construction, will burn out more rapidly at the lower part, around the crucible, than in that part which is above the top of the crucible, but as there is less brick-work, and as each furnace is detached from the others, they are more easily and speedily taken down and rebuilt than thosehere tofore used. But with my construction of furnace it'is not necessaryto take down the upper half of the brickwork in order to rebuild the lower half. This I accomplish by means of pins or bolts, .9, inscrted through slots t in the casing, at a point about half way between the top and'bottom of the furnace. These pins 8 are inserted at several points around'thc furnace, all at the same level and under the same course of brick-work. By means of clamps at these pins .9 may be secured in their position, so that they will not sink, but will hold up the brickwork situate above them, even when all the courses of bricks below them are removed. When the furnace is in operation the clamps a are left loose, so that the bolts or pins 8 s will not interfere with the settling of the brick-work, or its expansion or shrinking by the changes of temperature. When, however, itbeeo'mesneeessary to repair the brick-work of the furnace, or to remove and rebuild the lower courses of brick-work, the clamps u are raised up to the bolts or pins and fastened in that position, after which all the brick=work below the pins 8 may be removed with impunity, and new brick-work substituted. When the repair is finished the clamps u are loosened, which allows the superposed brick-work to bear upon the newly-laid bricks, and prevents the separation of the old and newwork by subsidence or otherwise. As the lower portion of the brick-work will burn out and require renewal about once in every six weeks, while the upper portion will ordinarily last from nine to twelve months, the saving, in material, time, ind trouble, effected by this arrangement is very obvious.

These furnaces are ordinarily built to hold two crucibles, which are placed as shown in fig. 2, supported over the grating on an inverted half of an old crucible, z. I

The legs bl), on which the furnaces are supported on the piers a, may be dispensed with, the iron casing of the furnace resting directly upon the piers, in which case air-passages should be made to connect the spaces m around the furnaces with the ash-pits d under the furnaces, so as to allow air to circulate around the iron'casings 0f the furnaces, and prevent their getting too hot.

Having thus described my improvement, what Iclaim as my invention, and desire to secure by Letters Potent, -is

1. Constructingmelting-furnaces for manufacture of steel, with iron casing or shell, lined witlffiiebrick, substantially as and for the purposes hereinbefore described.

2. The use, in combination with the iron casing ;or shell of steel-furnaces, of supports for upholding the upper portion of the brick lining, while the lower portion is removed or repaired, substantially as hereinbefore described.

3. The air-holes z'z'around the grating at the bottom of steel-furnaces, to allow the air to enter between the grate-bars all around, for the purpose of equalizingthe combustion of the fuel within the furnace.

In testimony whereof I, the said WILLIAM SwINDELL, have hereunto set my hand.

- WILLIAM SWINDELL. Witnesses:

JOHN LETZKUS, A. S. NICHOLSON. 

